Polyamine microcapsules featured with high storage stability used for one-component epoxy adhesive

摘要

One-component epoxy adhesives have great promising prospects in industrial applications. However, it faces the challenge to reduce the activity of curing agents for achieving long-term storage and controlled release. Microencapsulation is a feasible and effective solution. In this paper, multi-polyaniline (MPAN) was successfully encapsulated with polyetherimide (PEI), a thermoplastic resin, as the shell material by using solvent evaporation method with dichloromethane (DCM) as solvent. The impacts of different preparation parameters on the structure and properties of microcapsules were investigated by single variable control method. It is found that the resulted microcapsules under the optimal process parameters, namely PVA concentration 1 wt%, core/shell mass ratio 1:1 and stirring rate 700 rpm, exhibits a smooth and dense spherical surface with an average particle size concentrated around 17.8 mu m. Compared with the pure curing agent, the encapsulated curing agent effectively prolonged the shelf life of the epoxy adhesive at 40 degrees C for at least 60 days, indicating excellent storage stability. The microencapsulated MPAN curing agent prepared in our research is of potential applications in the fields of electronic component bonding, potting and circuit board sealing due to its high storage stability and encapsulation efficiency (74%).